Section

An elastic or mechanical wave can be defined as a perturbation that propagates in space, transporting energy but not material. A mechanical wave can only propagate thanks to the elastic properties of the material in which it originates. Due to the wave propagation the material undergoes to an elastic deformation: the particles that constitute the material move from their equilibrium position and return thereafter thanks to the elastic forces of recall. This way, the mechanical energy (kinetics and elastic potential) of an element it is transmitted to the adjacent one. A transverse wave occurs when the particles of the material move perpendicular to the wave’s direction and a longitudinal wave when they move in the same direction of the wave
Elastic waves can undergo the following effects:
1. Reflection: a wave that meets along its path a surface of separation between two means, reflects part of its component
2. Refraction: wave undergoes a deviation when it passes from a physical medium to another, changing the propagation speed;
3. Diffraction: a wave, after having encountered an obstacle along its path, deviates his path;
4. Interference: the superposition of two light beams at a given point, leads to a destructive or additive behavior of the waves.